Update on Lepton Jets MET mSUGRA LM1: Systematic Uncertainty Decomposition

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Update on LeptonJetsMETmSUGRA LM-1Systematic
Uncertainty Decomposition

• Rick Bobby

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Motivating ExampleMET (uncorr) From Towers
Total Background LM-1 Signal
Events
Rapidly falls
HLT Applied
?
Since this is a Counting Experiment, look at
cumulative events passing cuts
Flatter
MET GeV
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Motivating ExampleMET (uncorr) From Towers
Total Background LM-1 Signal
Rapidly falls - ?B / ?MET large
Naïve expectation Small systematic
effects affecting MET might lead to large
differences in S / SB
Cumulative Num. Events Passing Cut
Flatter ?S / ?MET small
Cut on MET GeV
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Uncertainty Definitionsconsidered so far

• Statistical
• SB
• Systematical
• Finite MC Statistics
• NW / Ngen
• QCD level (not shape)
• 50
• Jet Energy Scale
• 10 ET
• (affects also MET)
• Jet Energy Resolution
• Additional one ?ET smearing (?ET taken from the
  DAQ TDR)
• (affects also MET)

• For Jet Systematics
• N number of events passing cuts before
  systematic effect applied
• Nsyst number of events passing cuts after
  systematic effect applied
• Uncertainty number of events
• ?B N Nsyst

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Uncertainty Definitionsconsidered so far
Quick side remark 10 seems conservative for
this study (we assumes 10 fb-1) Plan to vary JES
systematic according to expected dependence on
integrated luminosity 8-10 for L lt 1fb-1 3
at some point after 1fb-1

• Statistical
• SB
• Systematical
• Finite MC Statistics
• NW / Ngen
• QCD level (not shape)
• 50
• Jet Energy Scale
• 10 ET
• (affects also MET)
• Jet Energy Resolution
• Additional one ?ET smearing (?ET taken from the
  DAQ TDR)
• (affects also MET)

• For Jet Systematics
• N number of events passing cuts before
  systematic effect applied
• Nsyst number of events passing cuts after
  systematic effect applied
• Uncertainty number of events
• ?B N Nsyst

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Uncertainty Definitionsconsidered so far
Quick side remark 10 seems conservative for
this study (we assumes 10 fb-1) Plan to vary JES
systematic according to expected dependence on
integrated luminosity 8-10 for L lt 1fb-1 3
at some point after 1fb-1

• Statistical
• SB
• Systematical
• Finite MC Statistics
• NW / Ngen
• QCD level (not shape)
• 50
• Jet Energy Scale
• 10 ET
• (affects also MET)
• Jet Energy Resolution
• Additional one ?ET smearing (?ET taken from the
  DAQ TDR)
• (affects also MET)

• For Jet Systematics
• N number of events passing cuts before
  systematic effect applied
• Nsyst number of events passing cuts after
  systematic effect applied
• Uncertainty number of events
• ?B N Nsyst

Many systematics not yet considered (PDFs, muon
ID eff, etc)
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Systematic UncertaintyDecomposition
Statistical MC Statistics QCD Jet E Scale Jet E
Resolution Total
HLT Applied
Uncertainty number of events
Cut on MET GeV
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Toy Significance Decomposition
NOTE The following plots have HLT
applied, MET cuts applied NO OTHER CUTS
APPLIED! ? significant optimisation
still possible (likely)

• Statistical only
• S / S B
• Statistical MC Statistics
• S / S B ?BMC2
• Statistical QCD level
• S / S B 0.5BQCD
• Statistical Jet Energy Scale
• S / S B ?BJES2
• Statistical Jet Energy Resolution
• S / S B ?BRES2
• Total
• S / S B ?BMC2 0.5BQCD ?BJES2 ?BRES2

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Toy Significance Decomposition
Statistical only Statistical MC
Statistics Statistical QCD Statistical Jet E
Scale Statistical Jet E Resolution Total
Significance
HLT applied, MET cuts applied NO OTHER CUTS
APPLIED! ? significant optimisation
still possible (likely)
Inclusion of different systematics tend to prefer
higher MET cut values
HLT Applied
Cut on MET GeV
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Observations

• Systematics in toy significance definition
• Shift to higher MET cut values preferred
• Overall reduction in toy significance
  estimation
• JetMET Uncertainties
• Current choices dominate (no JetMET
  recommendation yet)
• Jet Energy Scale 10 ET
• Jet Energy Resolution additional one unit of
  ?ET smearing
• Finite MC Statistics Uncertainty
• Important, but does not currently dominate!!
• Finite MC Statistics NW / Ngen
• QCD Level (not-shape) Uncertainty
• Not important compared with others (but, prob.
  too optimistic)
• QCD level 50

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Conclusion

• Everything still very preliminary!
• Healthy discussion about Finite MC Statistics
  Systematic arising from 06 Sept. SUSY/BSM Meeting
• Selection optimisation underway
• Toy significance estimate currently being used
• Inclusion of systematic effects being studied
• Likelihood ratio method being implemented
• Will be used for final results
• Early observations suggest that
• Systematics can have a strong effect
• JetMET systematics are important to understand
  and correctly estimate
• Current assumptions may be conservative?
• Need official recommendation from JetMET assuming
  10 fb-1 data collected
• We are still collecting additional statistics
• Y. Pakhotin has produced trees for all available
  ttbar!
• We are working to include more Wjets
• Will include Alpgen samples when available